The present disclosure relates to an optical sensor used to correct skewing of a conveyance belt provided in an image forming apparatus such as an inkjet recording apparatus.
An inkjet recording apparatus typified by an inkjet printer records an image on paper by selectively ejecting ink droplets from a recording portion onto paper conveyed on a conveyance belt which is an endless belt. When the conveyance belt skews due to the conveyance belt shifting in the width direction of the conveyance belt (in other words, toward the near side or the far side within the inkjet recording apparatus), the position at which the image is recorded on the paper shifts relative to the position at which the image was originally supposed to have been recorded.
In view of this, an inkjet recording apparatus having a function of detecting the position of a side face of the conveyance belt in the width direction of the conveyance belt with an optical sensor, and correcting skewing of the conveyance belt has been proposed. This inkjet recording apparatus is provided with an endless belt whose side edge portions are formed nonlinearly, a belt moving portion, an optical binary sensor that is disposed so as to oppose a side edge portion of the endless belt and that detects the presence of the endless belt, and a control unit that corrects shift of the endless belt by controlling the belt moving portion based on detection results of the binary sensor.
A photo-interrupter provided with a light emitting portion and a light receiving portion may be used as the optical sensor for detecting the position of the side face of the conveyance belt.